1. Field of the Invention
The present invention relates generally to computer graphics, and more particularly to a texture procedure for rendering curved bounded images on a graphics display device.
2. Related Art
A typical computer generated image of a curve bounded object utilizes a number of line segments to approximate the curved boundary. A pixel is a picture element of a graphics display device. Each pixel may represent unique attributes such as color, lighting, texture, etc. As is well known in the relevant art(s), texture procedures may be used to provide visual detail for displayed graphical objects. In a line segment technique, the more line segments used in the representation, the greater accuracy the ultimate display may contain. Each segment may contribute to one or more pixels of the final image. However, the number of line segments that can be used to render a display of a curved bounded region is limited. It is limited by the resolution of the intended graphics display device as well as the available memory space on the computer system. Furthermore, the more line segments used, the greater will be the calculation time, and thus the rendering time.
Conventional textures are image-based and composed of texels, which taken collectively form an image. A polygon is rendered with a mapping specified between the polygon's vertices and the texture. This mapping is usually specified in texture coordinates (s, t). When the polygon is rendered into pixels, the texture coordinates of each pixel are determined and used to lookup a value in the texture that is used in the drawing of the pixel. This value may be color, transparency, etc. Other conventional methods for rendering curved bounded regions have attempted various polygonal approximations and other incremental methods that result in the same limitations described above with respect to line segment techniques. Therefore, what is needed is a texture procedure for rendering curved based objects without the need to convert the graphics object into line segments or perform any type of tessellation.